Which of the following primary factors cause variations in insolation received at the surface of the earth? 1. Rotation of earth on its axis 2. Angle of inclination of the sun's rays 3. Altitude 4. Length of the day 5. Transparency of the atmosphere 6. Configuration of land Choose the correct answer from the options given below:

With reference to the Madden-Julian Oscillation (MJO), consider the following statements: I. It is an eastward-moving tropical disturbance rather than a stationary atmospheric trough. II. It is associated with alternating phases of enhanced and suppressed cloudiness, convection and rainfall. III. It generally operates within the tropical belt between 30°N and 30°S latitudes. IV. It can influence monsoon variability as well as tropical cyclone activity. Which of the statements given above are correct?

Which of the following correctly explains the formation of clouds in the atmosphere?